With the continuous development of economy, a processing amount of banknotes becomes larger and larger, and the requirements for a processing capacity of banknote processing devices is increased accordingly. The banknote processing devices widely used at present include an automatic teller machine, a banknote sorting machine and etc. according to main functions of the banknote processing devices. In these banknote processing devices, an impeller type banknote separation device is widely used.
The impeller type banknote separation device mainly includes an impeller, a banknote passage, an impeller position sensor, and a detection sensor for detecting whether the banknote enters. The detection sensor for the banknote is generally arranged on a passage close to the impeller. In the case that the banknote enters the impeller, the detection sensor is blocked (off), and the presence of the banknote is detected. With the rotating of the impeller, the banknote leaves the sensor, and the detection sensor is unblocked again (on). The impeller stops and waits for a next piece of banknote. Since an optical through-beam type sensor is generally used as the detection sensor for the banknote, and when the impeller rotates, unblocking the through-beam type sensor again from blocking state takes a long time, which results in a long detecting and processing time, and adversely affects a processing speed of the entire device. Additionally, in the case that the through-beam type sensor is used over a long time, the surface of the through-beam type sensor is apt to be covered by dust, which may also adversely affect the accuracy of detection.
Furthermore, since the banknote detection sensor in the conventional technology is arranged at the passage close to the impeller, the banknote detection sensor senses the banknote by sensing whether the banknote is to enter the impeller, and in fact, it cannot be ensured whether the banknote is completely inserted into the impeller. Therefore, a condition that the impeller starts to rotate when the banknote is not completely inserted in the impeller may occur, which may cause the banknote to fly off the impeller or be jammed during the delivering process.